The gastrointestinal tract is made up of a group of hollow organs which are joined in a muscle tract that extends from the mouth to the anus. The digestive tract is divided into the following sections: esophagus, stomach, small bowel, colon, rectum and anus.
The esophagus is a muscle tube of approximately 25 cm in length, whose main function is to carry food to the stomach. Both the upper and the lower esophageal sphincters are located at either end of it. These muscle sphincters help the esophagus empty out between swallows, and avoid regurgitation of gastric contents towards the esophagus, the larynx and the oral cavity.